W
White Room
I was told by my mate that when you use spirit level on vertical stuff door linings et. Level on side and then mesure of it top and bottom. Because if you use spirit level on other side there will be variation in distance due to spining movement of earth. He was told that by italian arhitect. As he was working there 12 yrs
A mate who's a brickie said the same similar about high rise buildings, due to the shape of the earth levels would be useless on the external walls